Just tried to do it but I got strange behavior in the mV range from the UT210E and the Brymens.
The waveform was just a pure (
positive) sinewave at 60hz.
The reference multimeter that was agreeing with the oscilloscope was the UT136C...
Probably because of its mV auto ranging. But have a look at the other multimeters.
(sorry for the bad image quality)
@ 30mV
@104mV
@178mV
@223mV
@301mV we lose the UT61E probably because of its 22000 counts limit.
It correctly displays -OL-
@406mV
@520 mV we lose both the UT210E and the Brymen BM869s.
The UT210E behaves here as a 4000 count meter!
The Brymen BM869s stays always below 440mV (50.000 count?) and even worse it does not display any warning!
@603mV
@722mV we also lose the Brymen BM235 as its a 6000 count meter, but again no warning
of the error!
@920mV the UT136C is the only one still displaying the correct value.
With a high crest factor things got more ugly.
So, the UT210E after the mod behaves as a 4000 count meter in the mVAC range...
The UT61E was the most well behaved which is to show that its still one of the best
low budget multimeters for low voltage electronics. That accuracy drift though...
The thing to note was that the Brymens displayed false readings without any warning.
* FAIL * for the expensive Brymens...